const a = ["one", "two"];
const b = new Map().set(0, "one").set(1, "two");
a.forEach((v, i) => console.log(`${v},${i}`)); // one,0  two,1
for (const [i, v] of b) console.log(`${i},${v}`); // 0,one  1,two
b.forEach((v, i) => console.log(`${v},${i}`)); // one,0  two,1
